1. Field of the Invention
The present invention generally relates to relieving congestion in a network fabric, or, more specifically, to pausing specific data flows within the network fabric.
2. Description of Related Art
Computer systems often use multiple computers that are coupled together in a common chassis. The computers may be separate servers that are coupled by a common backbone within the chassis. Each server is a pluggable board that includes at least one processor, an on-board memory, and an Input/Output (I/O) interface. Further, the servers may be connected to a switch to expand the capabilities of the servers. For example, the switch may permit the servers to access additional Ethernet networks or PCIe slots, as well as permit communication between servers in the same or different chassis.
A plurality of switches may be combined to create one logical switch. However, the communication interface between the logical switch and the servers may become so busy that packets are dropped (or lost). That is, a server may transmit packets to a switch faster than the switch can process the received packets. If the buffer associated with the switch fills up, subsequent packets may be dropped. To avoid packet loss, a switch may instruct the server to temporarily stop sending packets to the switch. The switch may use this period of time to relieve network congestion.